There are 33 known caribou herds inhabiting Alaska's 585,000 square miles of available habitat. Herds range in size from fewer than a hundred animals (Twin Lakes Herd) to concentrations exceeding 450,000 caribou (Western Arctic Herd). It's no wonder Alaska Department of Fish & Game (ADF&G) has had difficulties maintaining an accurate account of the state's caribou populous since their studies began around 1970. Most herds utilize separate habitats or ranges during each period of their lives.
These periods can be defined as times of the year in which caribou show habitual patterns, such as fall migrations to their wintering grounds or their aggregation during calving periods in the spring. While each herd chooses a variance of habitat in which to occupy during each period of the year, one factor remains congruent; each herd may encompass several Game Management Units, making surveys an extremely difficult undertaking for biologists.
The Western Arctic Herd (WAH), for example, is the largest group of caribou in the state, and these nomads are studied closely about every two years. These animals roam from Game Management Unit (GMU) 26 on the western arctic plains to GMU 21 in western Interior. This complexity of landmass and animal distribution consists of a range greater than 140,000 square miles of Alaska wilderness, earmarking the WAH as one of the most difficult herds to study with precision.
ADF&G biologists that share the responsibility for management of the WAH include Jim Dau, Kate Persons, Geoff Carroll and Glenn Stout. These professionals have the painstaking chore of locating, photographing, approaching and physically studying members of this herd. Once their research is complete, all data must be compiled and all discrepancies noted and resolved. Then, and only then, can the final conclusions of WAH behavior be drawn and published for the common hunter to review. Therefore, we hunters should be aware of all the perplexing issues and compromising factors involved with obtaining accurate field research. For simplicity, the WAH will remain the center of focus, as not to confuse this herd with any other caribou populous in the state.
Behavior Patterns Make Research Predictable
Since recorded history of the WAH began, research has remained consistent because of the predictable nature of this, and most every other herd. Biologists are able to pattern the herd's general movements and locate them easier from aerial surveys. During these studies biologists photograph every group of animals they spot; then they compile these photographs and count them repeatedly until a final number is agreed upon by all members of the survey team (usually three or more).
The accuracy of this method is somewhat open for criticism, as it is logical to believe that during the survey not all animals are accurately located and photograph. One factor limiting the survey's accuracy is the presence of 14 reindeer herds within the WAH's range. Over the past ten years members of the WAH have mingled with the reindeer along the Seward Peninsula, making it almost impossible to distinguish reindeer from WAH caribou during the time of surveys. Conversely, since thousands of caribou move within range of these reindeer, herders have reported losing more than 50 percent of their herds, as their reindeer defect to the migrating caribou. It is thereby reasonable to believe that the reported total population of WAH caribou can vary as a result of this mixing of wild and domestic caribou.
Accountability Often Difficult
ADF&G depends on hunter harvest data, local residential reports, field observations and historical surveys to keep a probable accountability on WAH caribou. The problem is that many hunters are not reporting accurate data of caribou harvests. It has become a serious problem with local natives subsisting off these caribou, as they often neglect to report any of the animals harvested for their village. This compromises accurate record keeping and animal population reports, as hundreds, if not thousands of caribou are taken each year without accountability. And although Alaska state law requires every resident to fill out harvest reports immediately following each big game hunting season, this law has never been enforced in rural areas.
Historical data on WAH caribou reveals a tendency for these animals to integrate and share ranges with other animals, as indicated by the reindeer incidence. It has also been documented that the WAH has aggregated in high numbers with other caribou on the fringes of their own historical routes of migration, such as the Teshekpuk Lake and Central Arctic herds. Although it is believed that caribou have a high fidelity to their native herd, it has been reported that thousands of caribou have crossed into other herds' territorial boundaries and remained for many months, making it appear as though one herd grew and the other(s) had a high mortality rate. Obviously this issue is considered when such observations are reported, but it has been known to fool some biologists, as with the 1983 survey of the WAH.
During this reporting period ADF&G reported that the WAH suffered unusually high mortality rates, killing nearly 30 percent of the herd. That would have meant the death of about 60,000 caribou. The following survey in 1986 showed the herd had rebounded to almost double the herd's total population, from approximately 120,000 to 220,000. It was immediately understood that the 1983 study was erroneous and therefore discounted as "difficult to believe that nearly one third of the WAH died" (Dau, 1999).
One gathers how it would be extremely frustrating to be responsible for surveying such a diverse group of animals, such as the WAH. Wildlife research is an area that demands strict patience and determination; one that is not, and never will be, a cut and dry process of obtaining accurate data. Hundreds of hours, thousands of dollars, lots of manpower and nearly perfect weather are needed to perform ideal surveys. Rarely is the case when all three components are available at the same time. This article is not to make a mockery of ADF&G biologists, but should shed light on the many idiosyncrasies of Alaska's caribou herds and the perplexities that continue to effect their management. It should be said that ADF&G biologists are an invaluable resource when researching any of Alaska's wildlife, as they have continued to provide the state, and its hunters with information that has allowed such hunting longevity.
Author / Wilderness Guide